The Declaration Refocus Program is the next generation M-WAZ imaging program in Mississippi Canyon in the U.S. Gulf of Mexico. The new, high-end re-imaging workflow is designed to provide enhanced imaging and greater illumination of prospectivity in the area. TGS is applying a combination of technologies including Dynamic Matching FWI to improve the velocity and salt model, and increase the frequency content in data. This reprocessing has strong support from many exploration and production companies and is targeting the Mesozoic level, including the highly prolific Norphlet play, as well as shallower horizons. The program comprises data covering more than 380 Outer Continental Shelf (OCS) blocks (~8,860 square kilometers) from orthogonal 3D WAZ programs acquired by TGS, between 2010 and 2015, using WesternGeco Q-Marine and CGG StagSeis seismic systems. Final data is now available.
Dynamic Matching FWI
Declaration Refocus is the first streamer reprocessing project to utilize Dynamic Matching Full-Waveform Inversion (DM-FWI) from TGS for a high-resolution velocity-model update, which focuses on solving kinematic difference between input data and synthetic data. With the data residual calculated in localized windows in time and space, DM-FWI provides a robust velocity-model update using the total energy in the data including both diving wave and reflections.
Declaration Refocus FWI before and after application of Dynamic-Matching FWI
The starting model ("before"), in the image above, shows legacy dual WAZ dataset (Declaration M-WAZ). The end model ("after") shows the final DM FWI derived Declaration Refocus model and image. Improved velocity model improves the imaging of salt and salt-related structures.
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